Camelina sativa cake and Cynara cardunculus meal into the diet of dairy goats affects the antioxidant activity and levels of total phenolic compounds in their milk

The incorporation of plant by-products in the ruminants’ diets may affect the composition of milk and may influence its functional activi- ties. Nevertheless, the bioactive compounds in goat’s milk have not yet received much study. Accordingly, the aim of this work was to quantify total phenolic compounds (TPC) and antioxidant capacity (AOX) in milk samples from goats fed a standard commercial diet supplemented with either Camelina sativa cake (Came) or Cynara cardunculus meal (Cardoon). The experiment lasted 3 wk. Eighteen multiparous and primiparous Alpine goats were divided in 3 homogeneous groups for parity (3 primiparous and 3 multiparous), milk production and days in milk (1.83, 2.23 kg, 273 DIM) and assigned randomly to 3 treatments: Came (n = 6) receiving 200 g/d of Came, Cardoon (n = 6) receiving 200 g/d of Cardoon and control (CT, n = 6) receiving the standard diet. Milk production, composition and live body weight were assessed weekly. Rumen content was sampled at d 0 and 21 on 3 goats per group selected by parity. Milk samples were collected at d 0, 7, 14 and 21. Milk col- lected at d 21 was in vitro digested with pepsin/pancreatin hydrolysis protocol. Milk digest was further analyzed for its antioxidant capacity by ABTS assay and for the total phenolic compound using Folin-Ciocalteu assay. Performance data were analyzed by PROC MIXED of SAS for repeated measures with diet, time and their interaction considered as fixed effect (LSM ± SEM). Significance was set at P ≤ 0.05. No differ- ences were observed in milk production, fat, protein, lactose content, live body weight and rumen pH during the trial among treatments. Milk urea decreased at d 14 in CT compared with Came and Cardoon (29.47 vs. 35.78 and 34.37 ± 1.68; P < 0.05) and at d 21 in CT and Cardoon compared with Came (20.35 and 20.90 vs. 26.42 ± 1.68; P < 0.05). Came and Cardoon milk showed higher antioxidant capacity (207.9 ± 4.25 and 195.4 ± 26.66 μmol Trolox equivalent/mL) compared with CT (115.6 ± 26.02 μmol Trolox equivalent/mL). Cardoon showed also higher TPC (32.49 ± 2.08 mg GAE/L) compared with CT and with Came. Came and Cardoon showed some interesting antioxidant activity on goat milk.